The UK public took a momentous decision when they voted to leave
the EU in a referendum on 23 June 2016. As is well known, the UK has, since the
entry into force of the Treaty of Lisbon on 1 December 2009, occupied a special
position in relation to the Area of Freedom, Security and Justice (‘‘AFSJ’’, Title V
TFEU). The Treaty introduced fundamental changes to the field of EU Criminal
Law, from which the UK had been sheltered through the opt in/opt out clauses as
well as the emergency brakes’ solution. This singular arrangement for the UK post-
Lisbon might, to some extent, have foreshadowed the present situation of Brexit, the
consequences of which for EU Criminal Law are inquired in this paper from a
Spanish perspective. It presents an analysis of what the alternatives to the current
relationship between Spain and UK could be in the future outside the EU framework,
while seeking to benefit from the improvements previously established through
European institutions and instruments. In this context, three different areas are
addressed: the interaction between Spain and UK in the context of European
agencies and institutions; the procedural framework in the area of judicial cooperation
through the application of the principle of mutual recognition; and, the
framework in relation to procedural rights through the application of the principle of
the approximation of laws. Finally, I conclude with some brief remarks on this
situation that is still unfolding.